1. Field of the Invention
Our present invention relates to a transfer adhesive tape of the type in which a carrier is provided with a contact-adhesive film which can be released from the carrier upon pressing of the adhesive layer against a substrate so that the adhesive layer will remain on the substrate and can be used to bond another surface thereto. More particularly, the invention relates to a transfer adhesive tape of this type wherein the adhesive film released by the carrier is a pressure sensitive adhesive of an acrylate base. The invention also relates to the production of such a transfer adhesive tape and to the use thereof in a hand held applicator.
2. Background of the Invention
Transfer adhesive tapes of the aforedescribed type have been provided heretofore and can be paid out from a roll of the adhesive tape in a hand held device which presses the tape against a substrate and thereby affects a transfer of the adhesive film to that carrier as the tape is wound back up on a take up roll of the device.
An apparatus of this type is described in EP 0 267 396 (see also U.S. Pat. No. 4,849,064, issued 18 Jul. 1989, U.S. Pat. No. 5,006,184, issued 9 Apr. 1991 and U.S. Pat. No. 5,125,589, issued 30 Jun. 1992).
The device comprises a housing in which a supply spool is provided for a carrier tape coated with the adhesive film, a take up roller for receiving the carrier tape after the adhesive film has separated therefrom, and a guide arrangement for deflecting the tape from the supply spool to the take up roll and supporting the tape at a location outside the housing at which the adhesive film coating side of the tape is disposed on the outside of the housing and can be transferred to the substrate.
Between the supply spool and the take up roll, a drive mechanism is provided which rotates the take up spool in step with the advance of the supply spool so that the support tape is continuously tensioned. In this manner, the adhesive film is released from the support tape and left adherent to the substrate. A further substrate, such as a piece of paper, can be applied to the adhesive coated surface thus produced.
Depending upon the type of adhesive film or its chemical composition, a permanent bond can be provided or lesser adhesion forces can be generated to enable the second substrate to be lifted from the first to which the adhesive strip can remain adherent.
In the adhesive film applications described above it has been found that the desired smooth tearing of the film when the device is moved away from the substrate, does not always result. In some cases, the separation of the film applied to the substrate and the device holding the transferring adhesive tape is so irregular that threads of adhesive are formed and create problems. A solution to this problem has not been devised previously.
In German Patent 22 25 618, for example, the problem has been unsuccessfully attacked by dividing the adhesive into segments on the tape so that tearing of the film can be avoided and thus separation of the film does not pose a problem in the first place.